Active Risk Squared- where do these numbers come from?

[rexthedog]

In Wiley Mok Q6 I am struggling to understnd where the table of answers provided are coming from:
The question gives the following:
Portfolo Industry Risk Index Total Active Factor Risk Active Specific Risk
A 3.6 11.4 15 10
B 4.5 7.5 12 4
C 6.5 4.7 11.2 4.8
The answer key has translated these to (respective to table above):
14.4% 45.6% 60% 40%
28.126% 46.87% 75% 25%
40.62% 29.375% 70% 30%
Where did these answers come from?

 

[S2000magician]

The numbers in each column are divided by the sum of the last two columns.
So, 14.4% = 3.6 / (15 + 10), 45.6% = 11.4 / (15 + 10), and so on.

 

[rexthedog]

That simple Thanks. Answer key didnt elaborate.

 

[S2000magician]

You’re welcome.

 

[rexthedog]

S2000 what ways can we calculate active risk on the exam day? Say for example we are given the active return but not the active risk how would we work that out for IR?
Active risk is Sd (rp-rb) but I have never seen a table give a single item for this?
Thanks